1. Technical Field
The present disclosure relates to a source driver and a display device having the same, and more particularly, to a source driver and a display device having the same for controlling gamma voltage.
2. Discussion of Related Art
Demand for flat panel display devices have rapidly increased because portable electronic devices are increasingly required to include a multimedia function. A thin film transistor liquid crystal display (TFT-LCD) device is a flat panel display device that has been widely used as a display device for portable electronic devices because of its light weight and low power consumption.
To be competitive in the current display market, it is desirable that the TFT-LCD device be of a high definition and a low price. The price of a TFT-LCD device can be reduced by reducing manufacturing costs through increased yields and use of less expensive components.
Various methods can be used to reduce the manufacturing cost of a TFT-LCD device. In one method, a process of fabricating the liquid crystal display (LCD) device is simplified. For example, thin film transistors in a display panel may be fabricated using amorphous silicon (a-Si:H) to reduce the number of masks. The amorphous silicon can be crystallized using a low-temperature poly silicon (LTPS) process to improve mobility of amorphous silicon. The LTPS process enables fabrication of thin film transistors having better carrier mobility compared to the amorphous silicon on an amorphous glass substrate. The process also enables circuits such as a gate driving unit and a source driving unit to be formed of a plurality of such thin film transistors and integrated inside a display panel.
Integration of such circuits on a glass substrate of the display panel can simplify the manufacturing process of the TFT-LCD device and reduce a manufacturing cost as well.
However, when the thin film transistor is fabricated using the LTPS process, threshold voltage and mobility are nonuniform and a kink effect takes place, thereby making it difficult to implement an analog circuit generating accurate voltage or current. Furthermore, when a source driving unit is integrated into a device other than the TFT-LCD device, an analog circuit of the source driving unit may need to be redesigned according to characteristics of a particular panel.
Thus, there is a need for a source driver and a display device having the same that generates more accurate current and/or voltage while reducing manufacturing costs.